An approximation for the reflectance from a semi-infinite medium
I introduce a simple analytical approximation for the reflectance from a semi-infinite medium which has scattering and absorption. Its inverse transformation (reflectance to scattering/absorption coefficients) has also simple analytical solution.
See build/transfer.pdf (currently written only in Japanese).
Although this work is original, it is obvious that similar works exist (…and they are most likely better than mine) since it seems a very basic and common problem. Unfortunately I cannot find them, at least freely avaiable on the Web. Let me know if you find them and I should cite them.
ks : Scattering coefficient ka : Absorption coefficient k : Attenuation (= ks + ka) R : Reflectance γ = 1.4 ks, ka => R P = sqrt(ka / (ks + ka)) R = (1 - P) / (1 + γ * P) R, k => ks, ka ka = k * ((1 - R) / (1 + γ * R)) ^ 2 ks = 1 - ka